Policy makers need to
be cautious in setting new ‘low-carbon’ standards for greenhouse gas emissions
for oil sands-derived fuels as well as fuels from conventional crude oils
University of Calgary and University of Toronto researchers say in a paper
published in Environmental Science &
Technology.
The researchers, using
for the first time confidential data from actual oil sands operations, did a ‘well-to-wheel’ lifecycle analysis of greenhouse gas emissions from
transportation fuels produced by Alberta oil sands operations compared with
conventional crude oils.
They found that
lifecycle greenhouse gas (GHG) emissions vary widely across both actual surface
mining and in situ oil sands
operations and conventional crude cases reported in the scientific literature,
depending on individual project operating conditions, technology used and other
factors. “Our study suggests it is not productive to get bogged down in a
debate over whether fuels derived from the oil sands emit 5% or 20% more GHG
emissions than fuels produced from conventional oils,” says Joule Bergerson,
who led the University of Calgary group for the study, with Heather MacLean who
led the University of Toronto group.
“We need to focus
instead on finding a transparent, consistent, and reliable way of accounting
for and reporting well-to-wheel greenhouse gas emissions across the industry
and the entire economy.” The research team developed a new model called GHOST
(GreenHouse gas emissions of current Oil Sands Technologies), which accounted
for the ‘upstream’ GHG emissions associated with the recovery, extraction,
dilution, transportation, and upgrading of bitumen. This data was combined with
information in the scientific literature on ‘downstream’ emissions from
refining, fuel delivery, vehicle refueling, and vehicle use, to arrive at the
comprehensive lifecycle analysis.
The team’s findings
overall supported the widespread perception that the production of
transportation fuels from the oil sands is more GHG-intensive than production
of fuels from conventional crude oil. However, the findings also show that some
lower-emitting oil sands operations actually can outperform higher-emitting
conventional crude cases in terms of GHG emissions intensity (the amount of
carbon dioxide emitted per barrel of fuel produced).
“The key message here
is that there are large, and overlapping, ranges of potential well-to-wheel GHG
emissions performance of both oil sands and conventional crudes. Therefore,
ranges rather than point estimates should be utilized to represent this
performance,” says Bergerson, an assistant professor of chemical and petroleum
engineering in the Institute for Sustainable Energy, Environment and Economy
and the Schulich School of Engineering.
Policies such as
low-carbon fuel standards and a focus on reducing oil sands operating emissions
alone is an initial step but will not be sufficient to achieve meaningful
long-term environmental policy goals, the researchers said in the study.
Vehicle operation, say
researchers, made up 64% to 74% of the wheel-to-well GHG emissions in the oil
sands operations. California’s Low Carbon Fuel Standard, which requires a
reduction in the state’s transportation fuels of at least 10% by 2020, “will be
complicated by the overlapping ranges of emissions associated with oil sands
and conventional crude pathways.”
The wide range of
potential emissions intensities for oil sands and conventional crude oils
suggests that treating all oil sands, whether surfacing mining or in situ, or all conventional crudes as
having the same level of emissions may lead to “unintended consequences,” say
researchers.
Source: University of Calgary
